diff --git a/apps/contourclock/custom.html b/apps/contourclock/custom.html
index 5047bdb06..a34953abe 100644
--- a/apps/contourclock/custom.html
+++ b/apps/contourclock/custom.html
@@ -4,9 +4,9 @@
 </head>
 <body>
   <form>
-    <input type="checkbox" id="Impact" name="Impact" value="0">
+    <input type="checkbox" id="Impact" name="Impact">
     <label for="Impact">Impact</label><br>
-    <input type="checkbox" id="Phosphate" name="Phosphate" value="1">
+    <input type="checkbox" id="Phosphate" name="Phosphate">
     <label for="Phosphate">Phosphate</label><br>
     <p>Click <button id="upload" class="btn btn-primary">Upload</button></p>
     <script src="../../core/lib/customize.js"></script>
